In a wireless communications system of a single-frequency network, all base stations send same cell signals, and user equipment (UE) on each base station edge may receive wanted signals of multiple base stations at the same time. In this way, better signal quality may be achieved, and a user throughput rate is improved. In a single-frequency network system, phases of base stations in a same cell need to be synchronized.
In the prior art, a Global Positioning System (GPS) is configured on each base station. The base station obtains a current absolute moment by using the GPS, and presets a moment for each base station. For example, 12 o'clock on Jan. 1, 2010 is used as a start moment of a subframe whose system frame number (SFN) is 0 and subframe number is 0 in a cell. Each base station calculates, according to the preset moment and the obtained current absolute moment, an SFN and a subframe number that are of a currently sent frame, so as to synchronize phases of signals between all base stations.
However, in the prior art, a GPS antenna needs to be installed during signal phase synchronization between all base stations. Consequently, costs are relatively high.